Re^5: $SIG{ALRM} and windows vista?

[BrowserUk]

Windows doesn't have signals

No, but it simulates some of them:

use strict;
use warnings;
use 5.010;

print 'Enter your password: ';

my $password = eval {
    local $SIG{ALRM} = sub {die "timeout\n"};
    alarm 5;
    #    return <STDIN>;
    sleep 10;
};

alarm 0;

if ($@ =~ /timeout/) {
    print "You timed out.\n";
}

__END__
[ 7:18:01.22] C:\test>alarmit.pl
Enter your password: You timed out.

[ikegami]

Partially, and therein lies the problem.

[afoken]

A little bit of bean counting:

Windows has no signals, and it does not emulate them. It's perl that implements an incomplete emulation of Unix signals, without support from Windows.

From perlport:

Don't count on signals or %SIG for anything.

Alexander

[BrowserUk]

It's perl that implements an incomplete emulation of Unix signals

If we're being pedantic, it is Perl on Windows that does the emulation.

Which is of course what I meant, though I agree, not exactly what I said.

[7stud]

On Windows Vista, your code doesn't do anything useful. Specifically, your code fails to display the message "Enter your password:" and then wait for the user to enter their password. Instead, your code does nothing, then prints out "Enter your password: you timed out."

In an effort to get "Enter your password: " to display immediately, I tried setting the output buffer to flush output immediately by setting $| = 1, but that didn't change the result.

[BrowserUk]

On Windows Vista, your code doesn't do anything useful.

It does! It demonstrates that alarm works, when the operation, (sleep in this case), doesn't involve IO. Ie. The sleep 10; was interupted by the alarm 5. And that was the only reason I posted it.

For a solution to your problem that works, see Term::ReadKey

[ikegami]

Instead, your code does nothing, then prints out "Enter your password: you timed out."

As it should. His code demonstrates that alarm will interrupt sleep on Windows.